<p>
    Implement a program that computes the maximum sum of any contiguous subarray of length exactly <code>window_size</code>. You are given an array <code>input</code> of length <code>N</code> consisting of 32-bit signed integers, and an integer <code>window_size</code>.
</p>

<h2>Implementation Requirements</h2>
<ul>
    <li>Use only native features (external libraries are not permitted)</li>
    <li>The <code>solve</code> function signature must remain unchanged</li>
    <li>The final result must be stored in the <code>output</code> variable</li>
</ul>

<h2>Example 1:</h2>
<pre>
Input:  input = [1, 2, 4, 2, 3], window_size = 2
Output: output = 6
</pre>

<h2>Example 2:</h2>
<pre>
Input:  input = [-1, -4, -2, 1], window_size = 3
Output: output = -5
</pre>

<h2>Constraints</h2>
<ul>
    <li>1 &le; <code>N</code> &le; 50,000</li>
    <li>-10 &le; <code>input[i]</code> &le; 10</li>
    <li>1 &le; <code>window_size</code> &le; <code>N</code></li>
</ul>